As a DSL operator you want to have enough confidence that the DSLAMs (Digital subscriber Line Access Multiplexer) that you put in the field are behaving as you expect they will, and that they are really capable of providing the services that you promise to your customers.
Here's an example testing service that Excentis can offer you. Suppose that your DSL-modems have two Ethernet ports: one is used to send IPTV traffic towards the IPTV Set-Top Box (STB), the other one is for normal data traffic (internet access).Excentis can perform stress tests where the DSLAM is fully loaded with several hundreds of DSL-modems that are all handling data and IPTV traffic. The DSLAM can be tested under several scenarios: all TV sets watching the same channel (all IP-STBs joining the same multicast stream), all TV sets watching a different channels (all IP-STBs joining a different multicast stream), all TV viewers zapping to a different channel, one by one or at the same time, anything you can think of. General stability can be tested, but also packet loss, jitter and latency over all devices, as well as e.g., the join-leave-gap and join-leave-overlap.